BRUNSWICK, Maine — A well-known Maine entrepreneur from the midcoast has joined the state’s venture capital fund to help mentor and grow its portfolio companies.

Des FitzGerald, best known for founding Ducktrap River Fish Farm Inc. in 1977 and growing it into a multimillion-dollar business, has joined the Small Enterprise Growth Fund as entrepreneur-in-residence.

The position is a new one, created to help the fund evaluate promising investment opportunities and provide a mentor who will be more heavily involved in helping portfolio companies grow their businesses, according to a media release. The fund has invested $13.4 million in approximately 45 companies since its inception in 1995.

After founding Ducktrap in 1977, FitzGerald led the company through significant growth through 1999, when he was named CEO of ContiSea, the holding company that merged Ducktrap and Atlantic Salmon of Maine to create an enterprise with more than 300 employees and more than $50 million in annual sales. ContiSea was sold to Continental Grain in 2002, according to the release.

FitzGerald has founded or co-founded three additional companies and been active as an adjunct professor in the University of Maine’s MBA program. Additionally, he was a founding member of Maine Businesses for Social Responsibility, now known as Maine Businesses for Sustainability; past president of the Natural Resources Council of Maine; and past board member of The Camden Conference, among other civic and private company board positions, according to the release.

John Burns, the fund’s manager, said FitzGerald’s “extensive experience” as an entrepreneur and “demonstrated leadership” make him “ideally suited to assist our portfolio companies in achieving their full potential, and to help identify and groom prospective portfolio companies.”

FitzGerald said he is looking forward to his new role.

“SEGF is an important facilitator in helping Maine’s emerging businesses gain their stride,” he said in a statement. “It’s not just about the money invested. A critical ingredient for sustained success is execution built on a commitment to functional leadership and a coordinated team with a shared vision. My role at SEGF will be to give the portfolio companies an additional in-house resource and give the team more capacity on the ground to identify and prescreen new opportunities to enhance the portfolio.”

The Maine Legislature created the Small Enterprise Growth Fund in 1995 as an investment vehicle to provide “patient sources of venture capital” to high-growth Maine companies. Its current portfolio of companies includes AIKO Biotechnology, Bar Harbor Biotechnology, Cerahelix Inc., and Looks Gourmet Food Co.